(1) Field of the Invention
The present invention generally relates to a control system for a multi-processor apparatus, and more particularly to a control system for controlling assignment of processes to processors in a multi-processor apparatus.
A facsimile machine in which processes, such as an editing process, a coding process and a decoding process, of document data including image data and text data are performed has a plurality of processors each of which carries out one of the processes.
The present invention provides a control system for controlling a multi-processor apparatus having a plurality of processors to use the processors so that the processes are efficiently executed.
(2) Description of the Related Art
A conventional multi-processor apparatus, such as the above facsimile machine, has, for example, special-purpose processors for a document editing process, an image superposing process, a coding process and a decoding process.
FIGS. 1A and 1B show examples of processes executed in the multi-processor apparatus, which processes are an editing process for performing enlargement conversion of a document and a superposing process for superposing graphics on document data.
In FIG. 1A, a process of the enlargement conversion of documents is illustrated. Referring to FIG. 1A, an A4 sized document data 101 is converted into a B4 sized document data 102 (enlarged document data). In this enlargement conversion process, both the character data and image data of original document data are enlarged, so that the enlarged document data is obtained.
In FIG. 1B, the superposing process for graphics is illustrated. Referring to FIG. 1B, a document 104 includes character data and has a blank space 104' over which graphics represented by image data 103 is to be superposed. The graphics represented by the image data 103 is superposed on the blank space 104' in the document 104, so that a document 105 including the character data and graphics 105' is obtained. In this superposing process, the character data is arranged so that the blank space 104' is formed in the document 104, and the image data 103 of the graphics is embedded in the blank space 104'.
FIG. 2 shows a structure of the conventional multi-processor apparatus.
Referring to FIG. 2, the multi-processor apparatus has an editing processor 110, a superposing processor 111, a coding processor 112, a decoding processor 113, an input-output control processor 114, a data memory 121, a program memory 122 all of which are coupled to each other by a bus 133. The editing processor 110 performs a process for editing document data. The superposing processor 111 performs a process for superposing image data on document data. The coding processor 112 codes data to obtain compressed data. The decoding processor 113 decodes the compressed data. The input-output control processor 114 performs an input-output control of data. The data memory 121 stores data used in this apparatus. The program memory 122 stores input-output control programs. This multi-processor apparatus has also an input unit 130, an output unit 131 and an input-output interface 132, the input unit 130 and the output unit 131 being coupled to the bus 133 via the input-output interface 132. The input unit 130 has a keyboard for inputting data and other devices for inputting received data from an external disc unit and a transmission line. The output unit 131 has a display device for displaying data, a printer for printing data and other devices for outputting transmission data to the transmission line.
The above multi-processor apparatus operates as follows.
Document editing data and image data input by the input unit 130 are supplied to the bus 133 via the input-output interface 132. The document editing data and image data are stored in the data memory 121 under the control of the input-output control processor 114. In the document editing process, the editing processor 110 processes the input data in accordance with an editing program. In a case where images are superposed on a document, the superposing processor 1ll processes document data and image data in accordance with a superposing program so that the images are superposed on the document.
If the input data is compressed data, the decoding processor 113 decodes the compressed data in accordance with a decoding program. The data processed by the respective processors is stored in the data memory 121. In a case where data in a document obtained by the processes is compressed and transmitted, the data, (including document data and image data) of the document, to be transmitted is compressed in accordance with a coding program, and the compressed data is supplied to the output unit 131 via the input-output interface 132.
In the conventional multi-processor apparatus, each of the processors is a special-purpose processor for a process. Thus, if an amount of data in a process assigned to a processor increases, a waiting time for the process to be executed by the processor increases. On the other hand, a processor to which a process having a small amount of data is assigned has a long idle time. Thus, in the conventional multi-processor apparatus, the utilization of the processors is low.